/*
 * Copyright (c) 2015 Sylvain Peyrefitte
 *
 * This file is part of mstsc.js.
 *
 * mstsc.js is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

(function () {
  /**
   * decompress bitmap from RLE algorithm
   * @param	bitmap	{object} bitmap object of bitmap event of node-rdpjs
   */
  function decompress(bitmap) {
    var fName = null;
    switch (bitmap.bitsPerPixel) {
      case 15:
        fName = "bitmap_decompress_15";
        break;
      case 16:
        fName = "bitmap_decompress_16";
        break;
      case 24:
        fName = "bitmap_decompress_24";
        break;
      case 32:
        fName = "bitmap_decompress_32";
        break;
      default:
        throw "invalid bitmap data format";
    }

    var input = new Uint8Array(bitmap.data);
    var inputPtr = Module._malloc(input.length);
    var inputHeap = new Uint8Array(
      Module.HEAPU8.buffer,
      inputPtr,
      input.length
    );
    inputHeap.set(input);

    var output_width = bitmap.destRight - bitmap.destLeft + 1;
    var output_height = bitmap.destBottom - bitmap.destTop + 1;
    var ouputSize = output_width * output_height * 4;
    var outputPtr = Module._malloc(ouputSize);

    var outputHeap = new Uint8Array(Module.HEAPU8.buffer, outputPtr, ouputSize);

    var res = Module.ccall(
      fName,
      "number",
      [
        "number",
        "number",
        "number",
        "number",
        "number",
        "number",
        "number",
        "number",
      ],
      [
        outputHeap.byteOffset,
        output_width,
        output_height,
        bitmap.width,
        bitmap.height,
        inputHeap.byteOffset,
        input.length,
      ]
    );

    var output = new Uint8ClampedArray(
      outputHeap.buffer,
      outputHeap.byteOffset,
      ouputSize
    );

    Module._free(inputPtr);
    Module._free(outputPtr);

    return { width: output_width, height: output_height, data: output };
  }

  /**
   * Un compress bitmap are reverse in y axis
   */
  function reverse(bitmap) {
    return {
      width: bitmap.width,
      height: bitmap.height,
      data: new Uint8ClampedArray(bitmap.data),
    };
  }

  /**
   * Canvas renderer
   * @param canvas {canvas} use for rendering
   */
  function Canvas(canvas) {
    this.canvas = canvas;
    this.ctx = canvas.getContext("2d");
  }

  Canvas.prototype = {
    /**
     * update canvas with new bitmap
     * @param bitmap {object}
     */
    update: function (bitmap) {
      var output = null;
      if (bitmap.isCompress) {
        output = decompress(bitmap);
      } else {
        output = reverse(bitmap);
      }

      // use image data to use asm.js
      var imageData = this.ctx.createImageData(output.width, output.height);
      imageData.data.set(output.data);
      this.ctx.putImageData(imageData, bitmap.destLeft, bitmap.destTop);
    },
  };

  /**
   * Module export
   */
  Mstsc.Canvas = {
    create: function (canvas) {
      return new Canvas(canvas);
    },
  };
})();
